Machine for making multi-duct concrete conduit



' Feb. 15, 1966 MC REW TAL 3,234,617

MACHINE FOR MAKING MULTI-D'JCT CONCRETE CONDUIT Filed July 6, 1964 3 Sheets-Sheet 1 20 67079.! C. Mr rew Feb. 15, 1966 J 3, c w ETAL 3,234,617

MACHINE FOR MAKING MULTI-DUCT CONCRETE CONDUIT Filed July 6, 1964 3 Sheets-Sheet 2 ovW ATTOR/Vf/J United States Patent 3,234,617 MACHINE FOR MAKING MULTI-DUCT CONCRETE CONDUIT James C. McGrew, Houston, and Robert W. Hoffman, Pasadena, Tex., assignors, by mesne assignments, of forty-four percent to Douglas N. Norton, twelve and one-half percent to Marion C. McKinley, seven and onehalf percent to H. W. Lehman, two and one-half percent to Ruth J. Garnett, four percent to John W. Brandenberger, two and one-half percent to Ida Perkins, one percent to Vernon G. Stamm, one percent to Henry J. Denton, one percent to Browning & Simms, twentytwo percent to William F. Newton, one percent to W. R. Sellers, and one percent to Glynn S. McClellan Filed July 6, 1964, Ser. No. 380,315 11 Claims. (Cl. 25-33) This invention relates to machines for manufacturing multi-duct concrete conduit such as utilized in the laying of underground communication cable or the like, and is generally of the type described in the Norton Patent No. 3,060,539, issued October 30, 1962.

As will be seen by reference to the said Norton patent, the conduit in such a machine is formed within a form disposed in vertical position in which the ducts in the conduit to be formed will be disposed vertically. The ducts are made within the concrete in the form by means of packer heads which are first lowered on shafts down through the form to the lower end thereof, after which concrete is fed into the upper open end of the form and the packer heads rotated and gradually withdrawn to pack the concrete Within the form and leave the ducts formed therein as the packer heads emerge from the upper end of the form. In order to provide a top for the form and arrange for feeding concrete into the form, a feed table was provided which was lowered onto and locked down on top of the rest of the form and which had openings therein corresponding in size and position to the upper ends of the ducts to be made in the conduit, and the concrete was fed into such holes around the shafts carrying the packer heads so as to fill the form.

The necessity for feeding this concrete mixture through the relatively small annular openings around the shafts carrying the packer heads was found to be a limiting factor in shortening the time cycle necessary for the production of each length of conduit, but the top of the form could not be left open during the final portion of the operation of the packer heads in making the ducts Within the conduit because this would permit the packer heads to throw concrete out of the form.

It is an object of this invention to provide a machine in which the advantages of the removable top or pallet closing the top of the form will be retained and yet in which the same will not interfere with the rapid feeding of concrete into the form to fill the same.

Another object of this invention is to greatly shorten the time required for filling a form in the manufacture of a length of multi-duct concrete conduit.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein is set forth by way of illustration and example one embodiment of this invention.

In the drawing:

FIG. 1 is a view in front elevation of a machine having one embodiment of the present invention incorporated therein, showing the feed table in elevated position such as it occupies while changing forms, but with the pallet mechanism in its lower position relative to the feed table, and showing a form in place ready for lowering of the table in the beginning of the filling operation, the feed table and the form being shown in vertical cross section;

FIG. 2 is a fragmentary view similar to the central portion of FIG. 1, showing the feed table resting on top of the open end of the form and the shafts which carry the packer heads extending toward the lower end of the form, with the pallet and pallet mechanism in raised position to permit the maximum space for feeding concrete into the form;

FIG. 3 is a top plan view of those portions of the machine illustrated in FIG. 2;

FIG. 4 is a view similar to FIG. 2 but showing the completion of the duct forming step with the duct forming packer heads emerging from the upper end of the form and the pallet and pallet lifting mechanism in lower position to provide a closure for the upper end of the form;

FIG. 5 is a side elevation of the structure shown in FIG. 4, taken along the line 5-5 of FIG. 4, with parts of the feeding table and upper end of the form broken away and shown in section for purposes of illustration.

In general the objects of this invention are accomplished in the disclosure contained in the drawings by providing the feed table which rests on top of the form during the form filling operation with an opening therein comparable in size to the upper end of the form, and in providing a separate pallet or form-closing member of a size adapted to close the upper end of the form except for the openings through which the duct forming mechanisms are moved into and out of the form, and providing means for lifting such pallet upwardly through the opening in the feed table and to a position above the feed table so as to leave free for purposes of filling the form the entire opening through the feed table into the upper end of the form. By this arrangement, when the packer heads are lowered into the form the only obstruction to the entry of concrete mix from the feed table into the form consists of the shafts on which the packer heads are carried, the entire upper end of the form being open except for the area occupied by the cross sections of such shafts. Then when the form has been filled and the packer heads are moving upwardly and forming the ducts in the concrete conduit, the upper end of the form will be closed to prevent throwing the concrete mix out of the form by the simple expedient of lowering the pallet into place to close the upper end of the form. Any final filling of the form with concrete mix may be accomplished after the pallet is in place in the upper end of the form through the openings provided in the pallet for the emergence of the duct-forming packer heads from the form. Means are provided for raising and lowering the pallet relative to the feed table, which in substance locks the pallet in its lower osition to prevent it from being pushed up by the pressure of the concrete in the form, and which raises and lowers all portions of the pallet at the same rate simultaneously so that it Will not become canted relative to the feed table, form and packer heads. Escape space is also provided just above the pallet for the escape of any excess concrete just before the rising packer heads start out through the pallet.

Referring more in detail to the accompanying drawings, the machine is illustrated in FIG. 1 as having a frame comprising side members 10 in upright position, a bottom cross member 12 interconnecting the side mem bers 10, and a top cross member 14 interconnecting the side members 10 at their upper ends. Rotatably mounted on the lower portion of the frame is a turntable 16 adapted to be locked during a form-filling operation in either of two positions by means of a latching bolt 18 mounted on the frame and engaging one of two keepers 20 mounted at diagonally opposite points on the turntable 16. The

3 bolt 18 may be retracted manually by means of a lever 22 pivoted on the side member of the frame so as to disengage the keeper and permit the turntable to be rotated for the purpose of transferring a filled form from the filling position and moving an empty form into the filling position.

A form 24 is shown in position ready to be filled in FIG. 1. As illustrated in FIG. 4, the lower end of this form will be provided with a lower end pallet 26 closing the lower end of the form except for openings in positions registering with the ends of the ducts to be formed in the conduit.

A feed table 28 is shown extending across the upper end of the form, spaced thereabove in FIG. 1 by a distance sufficient to make it possible to rotate the turntable 16 and move the form into or out of the filling position illustrated. This feed table is lowerable into engagement with the upper end of the form for the purpose of filling the form as illustrated in FIG. 2, being guided in such upward and downward reciprocation by means of guide pins 30 mounted adjacent its opposite ends and extending downwardly into engagement with guide bearings 32 mounted on the side members 10 of the frame. The feed table is effectively locked down when in lower position as shown in FIG. 5 by means of a lever shaped cam 29 at each end thereof pivotally mounted on the side frame member 10 at 31 just above the feed table when same is in its upper position and having its arm 33 adjacent such pivot of such a length that it will cam or wedge snugly against the top of the feed table when the feed table is in lower position. The opposite end of each of these lever cams is pivotally engaged to be lifted and lowered by a vertically extending rod 35 and when lifted will release the table for upward movement.

Located above the feed :table and in reciprocating guided engagement with suitable rails on the side members 10 of the frame is a cross head 34 extending the entire width of the frame. Interconnecting this cross head 34 and the feed table is a pair of lifting rods 36 fixedly secured by means of nuts 38 to the feed table on opposite sides of the position at which said table engages the upper end of the form. The upper ends of these lifting rods 36 extend slidably through suitable openings in the cross head 34 and have stop collars 40 mounted thereon in such position that when the cross head 34 reaches the uppermost position of its customary travel it will engage the stops 40 and lift the feed table off of the top of the form 24 to the position illustrated in FIG. 1 in which it will permit rotation of the turntable 16 and the removal and replacement of the form 24 by such rotation. The rods 35 likewise extend slidably through the cross head 34 and have stops 37 thereon so positioned that as the cross head moves upward it will first engage stops 37 and rotate lever cams 29 to positions releasing the feed table for upward movement, then engage the stops 40 to lift the feed table.

The cross head 34 is raised and lowered by means of suitable mechanisms such as actuating cables 42 passing over pulleys 44 on the upper cross member 14 of the frame and extending downwardly and being secured to the cross head at positions 46 adjacent the opposite ends of the cross head.

' Carried on the cross head 34 is a gear box 48 and suitable prime mover 50 for driving the shafts 52 that extend downwardly from the gear box 48 and carry on their lower ends duct-forming packer heads 54.

When the cross head 34 is lowered to lower the duct- 'forming packer heads 54 into the form 24, the feed table will be lowered by the rods 36 until it rests on top of the form 24 and the form 24 at its upper end will be centered into proper position with respect to the feed table by means of guide lugs 56 at spaced positions about the underside of the feed table.

For the purpose of closing the upper end of the form, when the feed table is in its lower position and toward 4 the close of the form-filling operation, a pallet 58 is provided of a size to fit the opening in the upper end of the form and close the same except for the openings 60 in the pallet 58 which are positioned and of a size corresponding to the positions and sizes of the upper ends of the ducts to be formed in the conduit by the filling of the form 24.

In the illustration, the pallet 58 is carried by means of spacers 62 interconnecting it with a pallet carrier plate 64, the latter being located above the bottom of the feed table 28 so that when resting on the bottom of the feed table or close to the bottom of the feed table it will suspend the pallet 58 below the feed ta'ble within the upper end of the form 24 in position to close such upper end. In order to provide for lifting of the pallet suspension plate 64 and of the pallet to the position illustrated in FIGS. 1 and 2, the plate 64 which is spaced above the pallet as shown at 66, is secured by means of bolts 68 to brackets 70 welded or otherwise suitably secured to bars or lifting brackets 72 which, as will be presently explained, are guided relative to the feed table and provided with means for moving them vertically away from and toward the feed table. Their movement toward the feed table is limited by two pairs of set screws 74 adapted to hold them far enough off of the feed table so that small amounts of concrete mix remaining on the feed table will not interfere with the brackets moving to a desired fixed spaced position above the feed table and thereby suspending the pallet 58 in the proper position in the upper end of the form 24. When so suspended in the upper end of the form closing same, the pallet will permit escape of excess concrete upwardly through openings 60 just ahead of the packer heads. Such concrete does not have to be pushed ahead of the packer heads all the way through the thickness of the feed table and plate 64, which would tend to cause jamming of the packer heads, but is permitted to escape laterally through the space 66 just above the pallet.

Provision for lifting and lowering the master pallet carrying plate 64 and hence the pallet 58 with respect to the feed table 28 includes two pairs of brackets 76 fixed to and extending from the floor of the feed table adjacent the brackets 72, each pair of brackets 76 having extending between them a bar 78 carrying upright guides 80. Each of the upright guides 80 adjacent the opposite end of the pallet lifting and lowering assembly is engaged by a slide pin 82 so that the pallet lifting and lowering assembly consisting of the pallet 58, the master pallet carrying plate 64, and the brackets 72 will be guided in its upward and downward movement so that it will move vertically substantially parallel to the shafts 52 and the ducts being formed in the conduit in the form 24, and prevented from rotation in a horizontal plane. It will be understood that the bolts 68 which secure the brackets 72 to the master pallet lifting and carrying plate 64 fit loosely in enlarged openings in the auxiliary brackets 70 so as to permit the master plate to be adjusted with respect to the brackets 72, but when the bolts 68 are tightened the entire assembly consisting of the master pallet 58, its suspension means 62, the master plate 64, and the brackets 72, will be one rigid structure and will be guided by the guides 80 in its upward and downward vertical movement toward and away from the floor of the feed table 28.

Rotatably mounted in each pair of brackets 76 adjacent the opposite ends of the master pallet lifting and lowering assembly is a shaft 84 each carrying adjacent its opposite ends a crank arm 86 and a crank arm 88, respectively. These crank arms on the two shafts 84 ineach case extend toward the central portion ofthe machine and toward one another so that their outboard ends overlie the pallet lifting and lowering assembly previously described. At such outboard ends they are connected by means such as links 90 to lifting lugs 92 mounted on the upper surfaces of the brackets 72. Adjacent one end of each of the shafts 84 is also provided an upwardly extending crank arm 94 and it will be readily apparent that when the crank arms 94 are moved to rotate the shafts in directions so that the arms 94 move away from one another, the result will be a lifting of the pallet lifting and lowering assembly to a position spaced above the floor of the feed table as illustrated in FIG. 2, and that when rotated in the opposite direction from that just mentioned so that the arms 94 move toward one another the result will be a lowering of the pallet lifting and lowering assembly until the same occupies the position relative to the feed table as illustrated in FIG. 1.

Mounted substantially over one edge of the feed table as illustrated in FIGS. 3 and 5, and in substantially the same plane as the arms 94, is a frame consisting of upright side members 96, bottom cross members 98 extending across the top of the feed table to support the side members 96, and a top cross member 100 interconnecting the side members 96. Suitable bracing is employed to render such framework sufficiently rigid. The upper cross member 100 is preferably formed of two channel sections or other suitable shapes somewhat spaced apart as shown at 102 in order to provide a balanced support for the mechanism now to be described.

Each of the arms 94 has pivotally secured to its upper end a pair of links 104, the opposite ends of which are pivotally secured to the lower ends of levers 106 each passing through the space 102 between the cross members 100 and pivoted thereto adjacent the center of each of the levers 106 as shown at 108. The upper end of one lever 106 opposite the links 104 is interconnected by means of a tie rod 110 with the lower end of the other lever 106, the connection of the upper lever 106 being at point 112 and that to the lower end of the opposite lever 106 being at 114. The upper end of the lever to which the tie rod 110 is connected at 114 is pivoted at 116 to the piston rod 118 of a piston and cylinder type hydraulic motor having a cylinder 120 pivotally mounted at 122 to a bracket 124 fixed on the upper cross member 100 of the frame.

It will be readily be observed that when the hydraulic piston and cylinder motor is actuated to cause the piston rod 118 to move out of the cylinder 120, the upper end of lever 106 to which it is connected will be rotated in a clockwise direction and the opposite lever 106 will be rotated an equal amount in the counterclockwise direction. These two rotations will simultaneously cause rotation of the two shafts 84 in a direction to move the levers 94 toward one another and the levers 86 and 88 in a downward direction to lower the pallet lifting and lowering assembly into engagement with the feed table as shown in FIG. 4. Conversely, operation of the hydraulic piston and cylinder motor in the opposite direction will cause the lifting of this pallet lifting and lowering assembly to the position spaced above the floor of the feed table as illustrated in FIG. 2. As shown in FIG. 4, when the pallet is down, each of the levers 106 and their associated links 104 will be in near alignment with each other, thereby offering almost a locking of the levers 86, 94 against rotation in a direction to raise the pallet relative to the feed table. Also each of the lever arms 86 will be in near alignment with their associated links 90, thereby otfering an additional almost locking effect preventing upward movement of the pallet under pressure of concrete in the form.

It will be observed that just as the set screws 74 limit the downward movement of the pallet lifting and lowering assembly and hence of the linkage which operates the same which has just been described, upward movement of this assembly will be limited by means of an adjustable screw 126 carried by the side member 96 of the frame adapted to form a stop for counterclockwise movement of the right-hand lever 106 as seen in FIG. 2.

In order to insure against the possibility of the master pallet being lowered into engagement with the bottom of the feed table, perhaps injuring a workman, each of the shafts 84 is provided with a lug 128. These lugs are so positioned that when the cross head 34 is in its lowermost position, as it is most of the time while the operator is working with his hands under the pallet scraping concrete mix from the feed table into the form, the cross head will engage such lugs and hold the shafts 84 with the pallet lifting and lowering assembly raised above the floor of the feed table and suspended and locked in such position.

For the purpose of operating the hydraulic piston and cylinder motor, the cylinder thereof is provided with connections to a fluid supply 130 and a valve 132 movable to one position so as to connect said fluid supply to the line 134 to one end of the cylinder while the other end of such cylinder is connected through a line 136 to a fluid return line 138. The valve 132 is movable to the opposite position wherein the fluid supply will be connected to the line 136 and the fluid return line 138 will be connected to the line 134 so that the fluid motor will be operated in the reverse direction.

In operation, a form 24 is placed on the turntable 16 while the feed table is elevated to the position shown in FIG. 1, and the turntable 16 rotated so as to place the form 24 in vertical alignment with the opening in the feed table.

Thereupon, downward movement of the cross head is initiated and the feed table will move downwardly with the cross head until it seats on top of the form 24, the form 24 being guided into register with the opening in the floor of the feed table by means of the guide lugs 56. As the cross head 34 continues to move downwardly the feed table supports 36 will stop when the feed table rests on top of the form 24 but the rods 35 will continue to move down until the cam levers 29 move to position locking the feed table down as shown in FIG. 5. Then the duct-forming packer heads 54 and their associated shafts 52 will continue to move downwardly into the form 24. During this movement the valve 132 will be actuated to lift the pallet lifting and lowering assembly until it occupies its lowermost position with the cross head resting on the shafts 84 and cooperating with the lugs 128 to keep the master pallet from being lowered. At this point concrete mix will be fed into the feed table through a suitable chute 140 and the operator will manually scrape such concrete mix from the floor of the feed table into the open end of the form 24. It is to be noted at this point that the opening in the feed table is substantially equal in size to the opening in the upper end in the form 24 so that the only obstruction to the feeding of concrete mix into the form 24 is the relatively small cross section area occupied by the shafts 52. During this time the pallet 58 will be in its elevated position as illustrated in FIG. 2 and completely out of the way of the feeding of concrete mix into the form. Hence such concrete mix can be fed in very rapidly until the form is substantially filled.

During the latter portion of the filling of the form, rotation of the shafts 52 through operation of the prime mover and the gear system 48 will be initiated, resulting in rotation of the duct-forming packer heads 54. After sufficient rotation of the packer heads 54 to cause the concrete mix to become packed in the lower portion of the form, elevation of the cross head 34 with its associated mechanism including the duct-forming packer heads 54 will be begun while the rotation of these packer heads is continued. When the form has been substantially filled and the packer heads near the upper end of their travel toward the upper end of the form, the operator will actuate the valve 132 and cause the lowering of the pallet lifting and lowering mechanism until the pallet passes through the opening in the feed table 28 and engages the open upper end of the form 24 to close the same except for the openings 60 therein through which the duct-forming packer heads 54 will emerge from the form.

After the upper ends of the packer heads 54 have passed into the openings 60 in the pallet 58 and the form packing has been substantially completed, the cross head 34 will engage the stops 40 on the upper ends of the feed table supports 36 and cause lifting of the feed table and the pallet lifting and lowering mechanism as a unit until they occupy the positions illustrated in FIG. 1. Thereupon, the feed table and its associated parts being lifted above the form into the position initially occupied when the form'was moved into position, the form, now filled with the multi-duct concrete therein, may be moved out of the way by rotation of the turntable 16. By placing an empty form on the turntable opposite the full form before such rotation, an empty form may be moved into position to be filled simultaneously with the removal of the full form.

Thereupon, the operation may be repeated.

From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

' The invention having been described what is claimed is:

1. In a machine for making multi-duct concrete conduit in a form having an open upper end and adapted to mould such conduit with the conduit ducts in vertical position, said machine comprising a frame, a support for such form carried on said frame, a feed table with an opening therein comparable in size to the open end of such form, means on said frame for supporting said table above and clear of such a form on said support to permit the form to be removed and replaced and also for supporting said table in feeding relation to such a form on 'said support, to permit concrete to be fed through the opening in the table into the open end of such form, a pallet adapted to provide the upper end of such form and having a plurality of openings therein of a size and position corresponding to the upper ends of the ducts of conduit to be made in such form, a plurality of duct forming means, and reciprocable means on said frame supporting said duct forming means from above said table and operahle to extend the duct forming means downwardly through the respective openings in said pallets and the opening in said table into such form and retract the same from such form, the improvement which comprises pallet lifting and lowering means supporting said pallet relative to said feed table for lifting said pallet above and spaced from said feed table to leave said feed table opening unobstructed by said pallet for feeding concrete therethrough and for lowering said pallet relative to said feed table into a position to provide the upper end of a form positioned on said support.

2. The improvement set forth in claim 1 in which said pallet lifting and lowering means includes a guide means interposed between said table and pallet, and means for applying a lifting and supporting force to said pallet with a resultant constantly tending to maintain said guide means in proper alignment.

3. The improvement set forth in claim 1 in which said pallet lifting and lowering means includes a plurality of coordinated lifting means in lifting-force transmitting engagement with said pallet at more than two spaced nonaligned positions respectively, whereby the attitude of said "pallet with reference to said table will be determined.

4. The improvement set forth in claim 1 in which said lifting and lowering means includes guide and slide elements carried by said table and pallet respectively for guiding said pallet along a path to register with the opening in said table as it approaches said table, and means for applying a lifting and supporting force to said pallet having its resultant in alignment with said path.

5. The improvement set forth in claim 1 in which said lifting and lowering means includes guide means for guiding said pallet along a path to register with the opening in said table as it approaches said table, and means for applying a lifting and supporting force to more than two spaced, non-aligned portions of said pallet to move the same bodily along said path without rotation relative to the direction of said path.

6. The improvement set forth in claim 1, in which said lifting and lowering means includes means for restraining said pallet against movement away from said form under pressure from within the form.

7. The improvement set forth in claim 1, in which said lifting and lowering means includes means engageable by said duct-forming means when in its lowermost position to restrain said pallet from moving downwardly from approximately its uppermost position relative to the feed table.

8. The improvement set forth in claim 1, in which said lifting and lowering means includes a pallet suspension plate, means supporting the suspension plate on said feed table when said pallet is in its lowermost position providing the upper end of a form, and means supporting said pallet from said pallet suspension plate in spaced relation thereto and below said plate to provide a lateral escape space for excess concrete between said plate and pallet.

9. In a machine for making multi-duct concrete conduit in a form having an open upper end and adapted to mold such conduit with the conduit ducts in vertical position, said machine comprising a frame, a support for such form carried on said frame, a feed table with an opening therein comparable in size to the open end of such form, means on said frame for supporting said table above and clear of such a form on said support to permit the form to be removed and replaced and also for supporting said table in feeding relation to such a form on said support to permit concrete to be fed through the opening in the table into the open end of such form, a master pallet carrying plate movably mounted on said table, a pallet secured to said plate in spaced relation to one side thereof and of a size to pass through the opening in said table and provide the upper end of such form and having a plurality of openings therein of a size and position corresponding to the upper ends of the ducts of conduit to be made in such form, means restraining and guiding movement of said plate relative to said table to bodily, nonrotative movement toward and away from said table, means for moving said plate toward and away from said table between a position in which said pallet is spaced above said table to leave said table opening unobstructed by said pallet for feeding concrete therethrough, and a position below said table to provide the upper end of a form positioned on said support, a plurality of duct-forming means, and reciprocable means on said frame supporting said duct forming means from above said table and operable to extend the duct forming means downwardly through the respective openings in the said pallet and the opening in the table into such form and to retract the same from such form.

10. A machine as set forth in claim 9 in which said means restraining and guiding movement of said master plate comprises a bracket adjustably secured to said plate along and adjacent each of two opposite extremities thereof, guide and slide means on each of said brackets and said table adjacent thereto for limiting movement of said combined brackets, master plate and pallet relative to said table to movement in a direction toward and away from said table, and coordinated lifting means interposed between said table and each of said brackets and engaging portions spaced longitudinally from each other along at least one of said brackets for moving all portions of said 3,234,617 9 10 brackets, master pallet carrying plate and pallet toward References Cited by the Examiner and from said table simultaneously and at the same rate.

11. A machine as set forth in claim 10 in which said UNITED STATES PATENTS lifting means comprises a pair of rotatable shafts mounted 1,433,300 10/ 1922 Quillet 2541 on said table and extending generally parallel to each of 5 2,341,012 2/1944 Biuman at aL said brackets respectively, a pair of identical cranks on 3 060 539 10/1962 N Orton each of said shafts, each crank being pivotally linked to spaced portions of said respective brackets, and means interlocking such shafts for simultaneous rotation at equivalent rates in directions to move both of said brackets 10 SPENCER OVERHOLSER, Primary Examinerbodily toward or bodily from said table.

3,091,831 6/1963 Rauch 25-36 

1. IN A MACHINE FOR MAKING MULTI-DUCT CONCRETE CONDUIT IN A FORM HAVING AN OPEN UPPER END AND ADAPTED TO MOULD SUCH CONDUIT WITH THE CONDUIT DUCTS IN VERTICAL POSITION, SAID MACHINE COMPRISING A FRAME, A SUPPORT FOR SUCH FORM CARRIED ON SAID FRAME, A FEED TABLE WITH AN OPENING THEREIN COMPARABLE IN SIZE TO THE OPEN END OF SUCH FORM, MEANS ON SAID FRAME FOR SUPPORTING SAID TABLE ABOVE AND CLEAR OF SUCH A FORM ON SAID SUPPORT TO PERMIT THE FORM TO BE REMOVED AND REPLACED TO SUCH A FORM ON PORTING SAID TABLE IN FEEDING RELATION TO SUCH A FORM ON SAID SUPPORT, TO PERMIT CONCRETE TO BE FED THROUGH THE OPENING IN THE TABLE INTO THE OPEN END OF SUCH FORM, A PALLET ADAPTED TO PROVIDE THE UPPER END OF SUCH FORM AND HAVING A PLURALITY OF OPENINGS THEREIN OF A SIZE AND POSITION CORRESPONDING TO THE UPPER ENDS OF THE DUCTS OF CONDUIT TO BE MADE IN SUCH FORM, A PLURALITY OF DUCT FORMING MEANS, AND RECIPROCABLE MEANS ON SAID FRAME SUPPORTING SAID DUCT FORMING MEANS FROM ABOVE SAID TABLE AND OPERABLE TO EXTEND THE DUCT FORMING MEANS DOWNWARDLY THROUGH THE RESPECTIVE OPENINGS IN SAID PALLETS AND THE OPENING IN SAID TABLE INTO SUCH FORM AND RETRACT THE SAME FROM SUCH FORM, THE IMPROVEMENT WHICH COMPRISES PALLET LIFTING AND LOWERING MEANS SUPPORTING SAID PALLET RELATIVE TO SAID FEED TABLE FOR LIFTING SAID PALLET ABOVE AND SPACED FROM SAID FEED TABLE TO LEAVE SAID FEED TABLE OPENING UNOBSTRUCTED BY SAID PALLET FOR FEEDING CONCRETE THERETHROUGH AND FOR LOWERING SAID PALLET RELATIVE TO SAID FEED TABLE INTO A POSITION TO PROVIDE THE UPPER END OF A FORM POSITIONED ON SAID SUPPORT. 